Production of aromatics from methanol and co-feeds

ABSTRACT

Methods are provided for improving the yield of aromatics during conversion of oxygenate feeds. An oxygenate feed can contain a mixture of oxygenate compounds, including one or more compounds with a hydrogen index of less than 2, so that an effective hydrogen index of the mixture of oxygenates is between about 1.4 and 1.9. Methods are also provided for converting a mixture of oxygenates with an effective hydrogen index greater than about 1 with a pyrolysis oil co-feed. The difficulties in co-processing a pyrolysis oil can be reduced or minimized by staging the introduction of pyrolysis oil into a reaction system. This can allow varying mixtures of pyrolysis oil and methanol, or another oxygenate feed, to be introduced into a reaction system at various feed entry points.

PRIORITY CLAIM

This application claims priority to and the benefit of U.S. ProvisionalApplication No. 62/057,855, filed Sep. 30, 2014, the disclosure of whichis incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

Methods are provided for the manufacture of aromatics from oxygenatefeeds.

BACKGROUND OF THE INVENTION

Conversion of methanol feeds to aromatic compounds is an industriallyvaluable reaction. Conventional methods for converting methanol toaromatics can involve exposing a methanol-containing feed to a molecularsieve, such as ZSM-5. In addition to forming aromatic compounds, someolefins can also be produced. Reactions for conversion of methanol canbe useful, for example, for creation of aromatics and olefins asindividual products, or for formation of aromatic and olefin mixturesfor use as naphtha boiling range or distillate boiling range fuels.

One difficulty with methods for conversion of methanol to aromatics isthat the conversion reaction can have a relatively low yield ofaromatics. The low yields from conventional methods can pose a varietyof challenges, such as requiring large equipment footprints relative tototal product volume as well as loss of initial reactant to various sidereactions.

U.S. Pat. Nos. 4,049,573 and 4,088,706 disclose conversion of methanolto a hydrocarbon mixture rich in C₂-C₃ olefins and mononucleararomatics, particularly p-xylene, by contacting the methanol at atemperature of 250-700° C. and a pressure of 0.2 to 30 atmospheres witha crystalline aluminosilicate zeolite catalyst which has a ConstraintIndex of 1-12 and which has been modified by the addition of an oxide ofboron or magnesium either alone or in combination or in furthercombination with oxide of phosphorus. The above-identified disclosuresare incorporated herein by reference.

Methanol can be converted to gasoline employing the MTG (methanol togasoline) process. The MTG process is disclosed in the patent art,including, for example, U.S. Pat. Nos. 3,894,103; 3,894,104; 3,894,107;4,035,430 and 4,058,576. U.S. Pat. No. 3,894,102 discloses theconversion of synthesis gas to gasoline. MTG processes provide a simplemeans of converting syngas to high-quality gasoline. The ZSM-5 catalystused is highly selective to gasoline under methanol conversionconditions, and is not known to produce distillate range fuels, becausethe C₁₀+ olefin precursors of the desired distillate are rapidlyconverted via hydrogen transfer to heavy polymethylaromatics and C₄ toC₈ isoparaffins under methanol conversion conditions.

Olefinic feedstocks can also be used for producing C₅+ gasoline, dieselfuel, etc. In addition to the basic work derived from ZSM-5 type zeolitecatalysts, a number of discoveries contributed to the development of theindustrial process known as Mobil Olefins to Gasoline/Distillate(“MOGD”). This process has significance as a safe, environmentallyacceptable technique for utilizing feedstocks that contain lowerolefins, especially C₂ to C₅ alkenes. In U.S. Pat. Nos. 3,960,978 and4,021,502, Plank, Rosinski and Givens disclose conversion of C₂ to C₅olefins alone or in admixture with paraffinic components, into higherhydrocarbons over crystalline zeolites having controlled acidity.Garwood et al have also contributed improved processing techniques tothe MOGD system, as in U.S. Pat. Nos. 4,150,062, 4,211,640 and4,227,992. The above-identified disclosures are incorporated herein byreference.

Conversion of lower olefins, especially propene and butenes, over ZSM-5is effective at moderately elevated temperatures and pressures. Theconversion products are sought as liquid fuels, especially the C₅+aliphatic and aromatic hydrocarbons. Olefinic gasoline is produced ingood yield by the MOGD process and may be recovered as a product orrecycled to the reactor system for further conversion todistillate-range products. Operating details for typical MOGD units aredisclosed in U.S. Pat. Nos. 4,445,031; 4,456,779, Owen et al, and U.S.Pat. No. 4,433,185, Tabak, incorporated herein by reference.

In addition to their use as shape selective oligomerization catalysts,the medium pore ZSM-5 type catalysts are useful for converting methanoland other lower aliphatic alcohols or corresponding ethers to olefins.Particular interest has been directed to a catalytic process (“MTO”) forconverting low cost methanol to valuable hydrocarbons rich in ethene andC₃+ alkenes. Various processes are described in U.S. Pat. No. 3,894,107(Batter et al), U.S. Pat. No. 3,928,483 (Chang et al), U.S. Pat. No.4,025,571 (Lago), U.S. Pat. No. 4,423,274 (Daviduk et al) and U.S. Pat.No. 4,433,189 (Young), incorporated herein by reference. It is generallyknown that the MTO process can be optimized to produce a major fractionof C₂ to C₄ olefins. Prior process proposals have included a separationsection to recover ethene and other gases from by-product water and C₅+hydrocarbon liquids. The oligomerization process conditions which favorthe production of C₁₀ to C₂₀ and higher aliphatics tend to convert onlya small portion of ethene as compared to C₃+ olefins.

The methanol to olefin process (MTO) operates at high temperature andnear 30 psig in order to obtain efficient conversion of the methanol toolefins. These process conditions, however, produce an undesirableamount of aromatics and C₂ olefins and require a large investment inplant equipment.

The olefins to gasoline and distillate process (MOGD) operates atmoderate temperatures and elevated pressures to produce olefinicgasoline and distillate products. When the conventional MTO processeffluent is used as a feed to the MOGD process, the aromatichydrocarbons produced in the MTO unit are desirably separated and arelatively large volume of MTO product effluent has to be cooled andtreated to separate a C₂-light gas stream, which is unreactive, exceptfor ethene which is reactive to only a small degree, in the MOGDreactor, and the remaining hydrocarbon stream has to be pressurized tothe substantially higher pressure used in the MOGD reactor.

U.S. Pat. No. 3,998,898 describes a method for manufacture of gasolineusing an MTG style process. In U.S. Pat. No. 3,998,898, a potentialgasoline including aromatic compounds is manufactured from a feed thatcontains two types of aliphatic compounds. The feed can containaliphatic compounds corresponding to a) “difficultly convertible”compounds, such as carboxylic acids and short chain aldehydes, and b)“easily convertible” compounds, such as aliphatic alcohols, ketones, andaldehydes containing 3 or more carbons, with the mixture havingsufficient “easily convertible” compounds to make up for astoichiometric deficiency due to the presence of any carboxylic acids inthe feed. The use of a mixture of a “difficultly convertible” compoundand an “easily convertible” compound meeting the specified criteria isdescribed as improving the yield of gasoline boiling range compounds atthe expense of compounds having 4 carbons or less.

U.S. Pat. No. 7,820,867 describes a variation on the methods from U.S.Pat. No. 3,998,898. The '867 patent describes integration of a reactionfor converting synthesis gas to methanol (or other oxygenates) with amethanol to gasoline reaction. In the integrated system, the“difficultly convertible” compounds can be introduced into the reactionstage for conversion of synthesis gas to methanol. The same definitionfor “difficultly convertible” compounds used in U.S. Pat. No. 3,998,898is maintained in the '867 patent.

Despite numerous prior art processes, there is an ongoing desire toimprove methods of converting methanol to aromatics that yield a higheramount of aromatics than the prior art methods. There is a particularinterest in methods that produce high yields of paraxylene, consideringparaxylene's value in industry and its use in the manufacture ofterephthalic acid, an intermediate in the production of syntheticfibers.

SUMMARY OF THE INVENTION

The present invention provides methods for improving the yield ofaromatics, particularly paraxylene, from conversion of oxygenate feedsincluding methanol. In one aspect, an oxygenate feed having an effectivehydrogen index of about 1.4 to about 1.9 is exposed to an aromatizationcatalyst under effective conversion conditions to form a conversioneffluent comprising one or more aromatic compounds. The oxygenate feedcontains 5 wt. % or less of carbon-containing compounds different fromCO and CO₂ that have a hydrogen index of 1 or less. Optionally, theoxygenate feed can be substantially free of carboxylic acids, such as afeed that comprises, consists essentially of, and/or consists ofketones, alcohols, C₃+ aldehydes, and combinations thereof.

In another aspect, methanol is reacted with a pyrolysis oil over anaromatization catalyst in a series of steps to form aromatics. Theintroduction of the pyrolysis oil is advantageously staged to reduce orminimize the coking and/or fouling effects of the reaction withpyrolysis oil. Thus, the total volume of the pyrolysis oil to be reactedis split into at least two portions, and each portion is fed, with anoxygenate feed (together “fresh feed”), to a reactor or series ofreactors at a different location to react with an aromatization catalystand the effluent from the previous step. Preferably, the volumepercentage of pyrolysis oil in each successive fresh feed increases, butless fresh feed is introduced at downstream entry points as compared tothe first entry point, and the total percentage of the pyrolysis oil inthe total amount of fresh feed is greater than the volume percentage ofthe pyrolysis oil of the feed introduced at the first entry point.

In one embodiment in which a pyrolysis oil is used as a co-feed, a firstfeed comprising a first oxygenate feed having an effective hydrogenindex of at least about 1 and a first portion of a pyrolysis oil feed isexposed to an aromatization catalyst at a first location under effectiveconversion conditions to form a first conversion effluent comprising oneor more aromatic compounds. The volume percentage of the first portionof the pyrolysis oil feed is about 5 vol % to about 25 vol % of thevolume of the first feed. At least a portion of the first conversioneffluent, along with a second feed comprising a second oxygenate feedhaving an effective hydrogen index of at least about 1 and a secondportion of the pyrolysis oil feed, is exposed to an aromatizationcatalyst at a second location under effective conversion conditions toform a second conversion effluent comprising one or more aromaticcompounds. The volume of the second feed is less than the volume of thefirst feed, and the volume percentage of the first portion of thepyrolysis oil feed based on the total volume of the first and secondfeeds is greater than the volume percentage of the first portion of thepyrolysis oil feed. Optionally, at least a portion of the secondconversion effluent, along with a third (or fourth, or fifth, etc.) feedcomprising a third oxygenate feed having an effective hydrogen index ofat least about 1 and a third portion of the pyrolysis oil feed, isexposed to an aromatization catalyst at a third location under effectiveconversion conditions to form a third conversion effluent comprising oneor more aromatic compounds.

In still another embodiment, an oxygenate feed having an effectivehydrogen index of at least about 1 and a pyrolysis oil feed isintroduced into a conversion reaction system at a plurality of feedentry points. The reaction system has a direction of flow, and each ofthe plurality of feed entry points is located at a different location ofthe reaction system relative to the direction of flow. The plurality offeed entry points includes at least a first upstream entry point and afinal downstream entry point. The portions of the oxygenate feed and thepyrolysis oil feed introduced at each of the plurality of feed entrypoints is exposed to at least a portion of an aromatization catalyst toform a plurality of converted effluents, and at least a portion of theconverted effluents from upstream feed entry points are combined withthe portions of the oxygenate feed and the pyrolysis oil feed introducedat a downstream feed entry point. The volume percentage of pyrolysis oilfeed based on the total volume of the portions of the oxygenate feed andthe pyrolysis oil feed is greater than the volume percentage of theportion of the pyrolysis oil feed introduced at the first upstream entrypoint. Optionally, the volume percentage of the portion of the pyrolysisoil at each feed entry point is greater than the volume percentage ofthe portion of the pyrolysis oil feed introduced at upstream feed entrypoints, the volume percentage of the portion of the pyrolysis oil feedbeing based on the total volume of the portions of the oxygenate feedand the pyrolysis oil feed introduced at the same entry point.Alternatively, the volume percentage of the portion of the pyrolysis oilfeed introduced at least two feed entry points is substantially similar.

The aromatization catalyst utilized herein comprises a molecular sieve,preferably ZSM-5, and at least one Group 8-14 element. Effectiveconversion conditions for the methods provided are a pressure of about100 kPaa to about 2500 kPaa, a temperature of about 300° C. to about600° C., and a weight hourly space velocity of about 0.1 hr⁻¹ to about20 hr⁻¹. The claimed methods and co-feeds provide an increased yield ofaromatics as compared to methods using methanol alone.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 schematically shows an example of a reaction system havingmultiple feed entry points for converting an oxygenate feed to formaromatics.

FIG. 2 shows results from converting feeds with various effectivehydrogen index values to form aromatics.

FIG. 3 shows an example of a bio-oil composition.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Overview

In various aspects, methods are provided for improving the yield ofaromatics during conversion of oxygenate feeds. An oxygenate feed cancontain a mixture of oxygenate compounds, including one or morecompounds with a hydrogen index of less than 2, so that an effectivehydrogen index of the mixture of oxygenates is between about 1.4 and1.9. Optionally, the mixture of oxygenates can include one or moreketones or aldehydes having 3 or more carbons. Additionally oralternately, the mixture of oxygenates can exclude compounds having ahydrogen index of less than 1 and/or can exclude carboxylic acids,formaldehyde, and acetaldehyde. An example of a mixture of oxygenateshaving an effective hydrogen index of between about 1.4 and 1.9 can be amixture of acetone, butanol (such as n-butanol), and ethanol. Such amixture of oxygenates can also include methanol and/or dimethyl ether.

In other aspects, a mixture of oxygenates with an effective hydrogenindex greater than about 1 can be converted with a pyrolysis oilco-feed. Pyrolysis oils are mixtures of oxygenates formed from pyrolysisof biomass in an atmosphere containing a reduced amount of oxygen.Pyrolysis oils can be difficult to process for various reasons,including an elevated content of oxygenates and aromatics as well as thepresence of substantial amounts of carboxylic acids. However, thedifficulties in co-processing a pyrolysis oil can be reduced orminimized by staging the introduction of pyrolysis oil into a reactionsystem. This can allow varying mixtures of pyrolysis oil and methanol(or another oxygenate feed) to be introduced into a reaction system atvarious feed entry points. This type of staged addition can allow foruse of increased amounts of pyrolysis oil in the overall feed for aconversion process while reducing or minimizing problems in a reactordue to plugging or formation of coke.

Hydrogen Index and Effective Hydrogen Index

In various aspects, an improved feed for forming aromatic compounds canbe provided by using a feed with an effective hydrogen index of lessthan 2, such as an effective hydrogen index of about 1.4 to about 1.9.The effective hydrogen index (EHI) of a feed can be calculated based onthe hydrogen index values of the components of a feed. In thisdiscussion, a reference to a hydrogen index or hydrogen index valuecorresponds to a value for a single compound, while an effectivehydrogen index represents a value for a feed containing one or morecomponents.

The hydrogen index (HI) of a compound containing only carbon, hydrogen,and oxygen can be expressed as HI=[n−2p]/m, where m, n, and p refer tothe stoichiometric values in a chemical formula expressed asC_(m)H_(n)O_(p). Based on this definition, examples of hydrogen indexvalues for oxygenate compounds are: aliphatic alcohols have a hydrogenindex of 2; acetone and propanal have a hydrogen index of 1.33 (C4+ketones and aldehydes have HI values between 1.5 and 2); acetaldehydehas a hydrogen index of 1; aromatic oxygenates (such as phenols) havehydrogen index values less than 1; and formaldehyde and sugars have ahydrogen index of 0. Carboxylic acids have a wide range of HI values,ranging from −1 for formic acid to greater than 1 for C5+ carboxylicacids. It is noted that benzene has an HI value of 1, while C7+ singlering aromatic hydrocarbons have HI values slightly greater than 1. Afterdetermining the hydrogen index values for the components in a feed, theeffective hydrogen index for the feed can be determined based on a moleweighted average of the hydrogen index values of the individualcomponents.

Mixtures of Oxygenates with Hydrogen Index of at Least 1

Hydrogen index can assist in characterizing a feed for conversion ofoxygenates to aromatics. For example, the formula for methanol (HI=2) isCH₄O. During a conversion reaction, the oxygen in the methanol typicallyforms water. After removing a water unit, the remaining atoms inmethanol correspond to a CH₂ unit. In order to form a C6 aromaticcompound (HI=1) from CH₂ units (HI=2), 6 additional hydrogen atoms (or 3H₂ molecules) have to be accounted for, such as by reaction with othercompounds. In other words, for an oxygenate to aromatics conversionreaction, a comparison of the hydrogen index for feed and productsindicates the amount of excess hydrogen atoms that have to be accountedfor. In a reaction environment for forming aromatics from methanol (orother oxygenates), these additional hydrogens have to be incorporatedinto other products from the conversion reaction. Conventionally, theadditional hydrogen atoms are accounted for by forming short chainaliphatic compounds, such as ethane and propane, which have astoichiometry of C_(n)H_(2n+2). Based on stoichiometry, in an idealizedreaction for forming benzene from methanol, this means at least threealkanes (ethane) have to be formed for each aromatic formed. This canresult in a substantial reduction in the yield of aromatics from theconversion process, as at least as many carbon atoms have to beincorporated into alkane products as are incorporated into aromaticproducts.

Instead of forming substantial amounts of alkanes, the additional H₂units can be consumed by hydrogenating compounds (such as oxygenatecompounds) with lower HI values. For example, formaldehyde has an HIvalue of 0. From a stoichiometry standpoint, 3 methanols plus 3formaldehydes can be used to form a C6 aromatic without requiringformation of additional alkanes. More generally, any compounds presentwithin a feed can potentially react with the excess hydrogen, includingcompounds that are not directly involved with formation of aromaticcompounds.

Under conventional methods, such as the methods in U.S. Pat. No.7,820,867, increasing the yield of aromatics from an oxygenate feed wasbelieved to require mixing of “easily convertible” compounds (having HIvalues greater than 1) with “difficultly convertible” compounds havingHI values less than 1. In such conventional methods, ketones and C3+aldehydes were considered “easily convertible” compounds, while allcarboxylic acids were defined as “difficultly convertible” regardless ofHI value. However, it has been unexpectedly determined that the yield ofaromatics can be improved using mixtures of oxygenates to form a feedhaving an effective hydrogen index of 1.4 to 1.9, where substantiallyall of the oxygenates in the feed have an HI value of greater than 1.Preferably, substantially none of the oxygenates in the feed arecarboxylic acids. An example of such an oxygenate feed can be a feedcomposed of alcohols, ketones, and C₃+ aldehydes that have a hydrogenindex of greater than 1. In such a feed, substantially all of thecomponents in the feed can represent compounds that are conventionallybelieved to be “easily convertible” compounds. However, an improvedyield of aromatics relative to feed with an EHI value of 2 (i.e., a feedof alcohols and/or dialkyl ethers) can still be obtained. A feed withsubstantially all components being “easily convertible” is definedherein as a feed containing about 5 wt. % or less of components thathave a hydrogen index less than 1 and/or that are carboxylic acids. Forexample, a feed with substantially all components being easilyconvertible can contain about 3 wt. % or less of components that have ahydrogen index less than 1 and/or that are carboxylic acids, or about 1wt. % or less, or about 0.5 wt. % or less, or about 0.1 wt. % or less.

One example of a feed that can have substantially all components thatare “easily convertible” compounds is a mixture of acetone, butanol(preferably n-butanol), and ethanol. Mixtures of acetone, n-butanol, andethanol are an example of a type of fermentation product that can beformed from fermentation of starch by some biological processes. Atypical yield from such a fermentation process (on a dry basis) can beabout 30 vol % acetone, about 60 vol % n-butanol, and about 10 wt. %ethanol in the product. This type of mixture of acetone, n-butanol, andethanol can be not only suitable for use in synthesis of aromatics, butcan in fact provide an improved yield relative to a pure alcohol feed.More generally, a variety of biological processes (such as fermentationprocesses) can produce mixtures of alcohols and ethers that also includeketones and C₃+ aldehydes. Such mixtures can have an EHI of less thanabout 1.9, thus allowing for use of the mixtures for conversion toaromatics with an improved yield of aromatics relative to a feed with anEHI of 2.

Mixtures of Oxygenates with Pyrolysis Oils (Staged Addition)

Another option for providing a process with improved aromatics yield canbe to use a traditionally lower value stream as a source of compoundswith low hydrogen index. Pyrolysis oils are an example of a potentialfeed stream containing low hydrogen index compounds. Pyrolysis oils caninclude a large variety of oxygenate and/or aromatic compounds, and thecomposition of pyrolysis oils can vary depending on the nature of theoriginal feed and the pyrolysis conditions. From an effective hydrogenindex standpoint, pyrolysis oils are a potentially useful co-feed for anoxygenate conversion process, as typical pyrolysis oils can have aneffective hydrogen index of less than 1. However, pyrolysis oils areconventionally viewed as less desirable for use as a co-feed duringconversion of oxygenates to aromatics due to an increased tendency forpyrolysis oils to coke and/or foul the conversion reactor. This cokingis believed to increase with increasing concentrations of pyrolysis oilin a feed for conversion.

An illustrative example of a possible pyrolysis oil composition is shownin FIG. 3. The composition in FIG. 3 was described in “ExploratoryStudies of Fast Pyrolysis Oil Upgrading”, F. H. Mahfud,Rijksuniversiteit Groningen, Nov. 16, 2007, ISBN 978-90-367-3226-9.

As shown in FIG. 3, a pyrolysis oil can contain a substantial portion ofaromatic compounds, such as syringols, furans, phenols, and guaiacols.Due in part to the presence of the aromatic compounds, incorporatingpyrolysis oils into a feed for an oxygenate conversion process isconventionally believed to lead to substantial coking of the catalyst.This coking can foul a conversion reactor and potentially preventoperation of the reactor at higher concentrations of pyrolysis oil in afeed.

In various aspects, the difficulties with coking in a conversion reactorwhen using a pyrolysis oil as a co-feed can be reduced or minimized bystaging the addition of the pyrolysis oil in a reaction system by usinga plurality of feed entry points. For example, in a reaction systemusing a series of reactors (or alternatively a series of feed entrypoints within a single reactor), the ratio of methanol (or another highEHI feed) to pyrolysis oil can be set separately for each reactor and/orfeed entry point. The ratio of methanol to pyrolysis oil in the firstreactor can be set to a relatively low value, so that 25 vol % or lessof the feed corresponds to pyrolysis oil. This can reduce or minimizethe coking in the initial reactor. The feed to the second reactor canthen correspond to the effluent from the first reactor plus anadditional amount of both the methanol and the pyrolysis oil. Based onthe presence of the effluent from the first reactor, a higher percentageof the fresh feed in the second reactor (feed entry point) cancorrespond to the pyrolysis oil. In an example using three feed entrypoints, the volume percentage of pyrolysis oil in the fresh feed to thesecond reactor can be at about 25 vol % to about 70 vol %, or about 25vol % to about 50 vol %. The effluent from the second reactor can thenbe used as a portion of the feed to a third reactor. The fresh feed tothe third reactor can include a still larger percentage of pyrolysisoil, such as about 40 vol % to about 80 vol %.

More generally, staging of addition of the pyrolysis oil in the feed tothe conversion reaction can be used with any convenient reaction systemconfiguration. The concept of staging is based on introducing a totalfeed to a reaction system by splitting the feed across multiple feedentry points at different locations relative to the direction of flowwithin the reaction system. Additionally, the composition of the feed ateach feed entry point will typically be different from the totalcomposition for the feed. The staging can be performed by using multiplereactors, with different concentrations of pyrolysis oil in the feed toeach reactor. Additionally or alternately, the staging can be performedby introducing feed in multiple locations (feed entry points) in areactor, with downstream locations in the reactor receiving greaterpercentages of pyrolysis oil in the feed. The staging of addition of thefeed can be used with fixed bed reactors, fluidized bed reactors, movingbed reactors, or any other convenient type of reactor. In some preferredaspects, the reactors used can be fluidized bed reactors or otherreactors that can facilitate regeneration and recycle of catalyst withinthe reactor.

In this discussion, references to introducing a feed or a co-feed at afeed entry point are understood as including any convenient method forintroducing a feed. For example, a high EHI feed (such as a methanolfeed) and a pyrolysis oil feed can be mixed prior to entering a reactionsystem via a feed entry point, or the high EHI feed and the pyrolysisoil feed can be introduced into a reaction system separately at similarlocations relative to the direction of flow within the reaction system.

The number of feed entry points in a reaction system having staged(different) amounts of pyrolysis oil in the fresh feed can be anyconvenient number. At least two different feed entry points are neededin order to have staged addition of the pyrolysis oil. In variousaspects, introducing the pyrolysis oil co-feed using three to eight feedpoints having different concentrations can be preferred. In order toavoid fouling, the highest pyrolysis oil volume percentage(concentration) at any feed entry point can be about 80 vol % or less.

When using multiple feed entry points for a feed including a pyrolysisoil, higher amounts of pyrolysis oil can be introduced into the later(downstream) feed entry points. Preferably, the amount of feedintroduced into a reaction system at all prior upstream feed entrypoints can be at least as great as the amount of feed introduced at anysingle downstream feed entry point. This can assist with providing asufficient volume of previously reacted feed so that production of cokedue to downstream introduction of pyrolysis oil is reduced or minimized

In various aspects, the combined amount of feed (high EHI feed pluspyrolysis oil feed) introduced at the first entry point can be at least20 vol % of the total amount of feed (high EHI feed plus pyrolysis oilfeed) introduced into the conversion reaction system, such as at leastabout 25 vol %, or at least about 30 vol %, or at least about 35 vol %.Additionally or alternately, the combined amount of feed introduced atthe first entry point can be about 75 vol % or less of the total amountof feed introduced into the conversion reaction system, such as about 65vol % or less, or about 50 vol % or less. In some aspects, after theinitial feed entry point, the combined amount of feed introduced at eachsubsequent feed entry point can preferably be at least about 5 vol % ofthe total amount of feed introduced into the conversion reaction system,or at least about 10 vol %. By staging the introduction of the pyrolysisoil, the net concentration of pyrolysis oil in the total feed across allfeed entry points can be as high as 70 vol %, such as about 15 vol % toabout 70 vol %, preferably about 25 vol % to about 70 vol %, and mostpreferably 50 vol % to 70 vol % of the feed.

In some alternative aspects, a single feed entry point can be used forintroduction of a pyrolysis oil co-feed. In such aspects, the amount ofpyrolysis oil used as a co-feed can be about 5 vol % to about 50 vol %,preferably about 10 vol % to about 40 vol %, and more preferably about15 vol % to about 30 vol %.

For a reaction system with a plurality of feed entry points, such as twoto eight feed entry points, or three to eight feed entry points, thepyrolysis oil concentration can vary at each feed entry point. For thefirst or initial feed entry point, the pyrolysis oil concentration canbe from 5 vol % to 25 vol % relative to the total weight of feedintroduced at the first feed entry point, preferably from 10 vol % to 25vol %, and more preferably from 15 vol % to 20 vol %. For the final feedentry point, the pyrolysis oil concentration can be from about 30 vol %to about 80 vol %, preferably about 40 vol % to about 80 vol %, morepreferably about 40 vol % to about 70 vol %, and even more preferablyabout 50 vol % to about 70 vol %. If three or more feed entry points areused, in some aspects at least one intermediate feed entry point canhave a pyrolysis oil concentration of about 25 vol % to about 50 vol %,preferably about 25 vol % to about 45 vol %, and more preferably about30 vol % to about 40 vol %. Additionally or alternately, if three ormore feed entry points are used, in some aspects at least oneintermediate feed entry point can have a pyrolysis oil concentration ofabout 35 vol % to about 60 vol %, preferably about 40 vol % to about 60vol %, and more preferably 40 vol % to about 55 vol %.

In some aspects, two or more of the feed entry points can have asubstantially similar concentration of pyrolysis oil. In other aspects,each subsequent feed entry point can have a higher concentration ofpyrolysis oil than the prior feed entry point, such as at least 5 vol %greater, or at least 10 vol % greater. Any convenient method or schemecan be used for varying the relative amounts of high EHI feed andpyrolysis oil feed at the various feed entry points. For example, oneoption can be to introduce the same amount of pyrolysis oil at each feedentry point while varying the amount of methanol (or other high EHIfeed) at the feed entry points to achieve the desired variation inpyrolysis oil concentration. Another option can be to introduce the sametotal weight of feed at each feed entry point while varying the amountsof high EHI feed and pyrolysis oil feed.

By using staged addition of pyrolysis oil, an increased amount ofpyrolysis oil can be used as a co-feed for conversion of oxygenates toaromatics while reducing or minimizing the amount of additional cokeformed in the reaction system. For the first reactor and/or first feedentry stage of the reaction system, the amount of coke generated in thereactor can roughly correspond to the amount of coke expected based onthe percentage of pyrolysis oil in the feed. However, for a second (orother subsequent) addition locations for the feed, the amount of cokecan correspond to an amount less than would be expected based onaddition of all of the pyrolysis oil with the initial feed. Instead, theeffluent from the earlier reactors (or upstream locations) can act as adiluent so that the amount of coke generated is comparable to what wouldbe expected based on the concentration of the fresh pyrolysis oil in thetotal input flow to a given reactor stage or location. It is also notedthat using staged addition of the pyrolysis oil can reduce or minimizethe amount of methanol that is consumed in alkylation of the pyrolysisoil instead of being converted to the desired aromatic compounds.

FIG. 1 schematically shows an example of a reaction system suitable forintroducing pyrolysis oil in a stage manner during an oxygenate toaromatics conversion process. For convenience in illustrating theconcept, FIG. 1 shows examples of both using multiple reactors forstaged addition as well as introducing feeds at multiple locationswithin a reactor. Of course, any convenient combination of additionalreactors and additional feed entry points can be used, such a reactionsystem using separate reactors for each feed entry point and/or areaction system comprising a single reactor with multiple feed entrypoints. The reactors in FIG. 1 can correspond to any convenient type ofreactor for stage addition of feed. For convenience, the reactors inFIG. 1 are shown as fixed bed reactors, but fluidized bed reactors orriser reactors could also be used.

In FIG. 1, two sources of feed for the reaction system are shown. Onefeed source 105 of feed is a feed with an effective hydrogen indexgreater than 1, such as a feed comprising methanol and/or dimethylether, or a feed comprising a mixture of alcohols and ethers. A secondfeed source 107 can provide a pyrolysis oil feed to the reaction system.FIG. 1 shows these feed sources schematically as corresponding tomultiple instances of feed sources for convenience. In other aspects, asingle high hydrogen index feed source 105 and/or pyrolysis oil feedsource 107 could be used. FIG. 1 also depicts introducing feed streamsderived from feed source(s) 105 and 107 as separate feed streams into areaction system at various feed entry locations. Of course, a feedstream comprising a mixture of feeds from a feed source 105 and a feedsource 107 can be mixed together prior to entering a reactor. Mixing apyrolysis oil with a methanol (or other high effective hydrogen indexstream) could be beneficial, for example, to provide better mixing priorto entering a reactor or to improve the flow properties of the pyrolysisoil feed for delivery to a reaction system.

In FIG. 1, feed streams 115 and 117 (from feed sources 105 and 107,respectively) are delivered to a first conversion reactor 120. Secondconversion reactor 140 similarly receives feed streams 135 and 137,along with first conversion reactor effluent 122. The feed streams 135and 137, along with first conversion reactor effluent 122, areintroduced into second conversion reactor 140 prior to an initialcatalyst bed 143. Feed streams 155 and 157 are introduced into reactor140 between initial catalyst bed 143 and final catalyst bed 144. At thelocation where feed streams 155 and 157 are introduced, the feed streamsare at least partially mixed with effluent from initial catalyst bed 143prior to passing through final catalyst bed 144.

For a configuration such as the reaction system shown in FIG. 1, therelative amounts of feed from feed sources 105 and 107 at each feedentry location can be varied so that the percentage of feed from feedsource 107 increases at later feed entry locations. For example, for acombined amount of feed delivered to the first conversion reactor 120,80 vol % of the feed can correspond to feed stream 115 from source 105,while 20 vol % can correspond to feed stream 117 from source 107. At thesecond feed entry location, 50 vol % of the fresh feed can be in feedstream 135 while the other 50 vol % can be in feed stream 137. At thethird (final) feed entry location, 30 vol % of the fresh feed can be infeed stream 155 while the remaining 70 vol % can be in feed stream 157.

Conversion Conditions

One option for performing an oxygenate to aromatics conversion reaction,such as a methanol to gasoline type process, can be to use a moving orfluid catalyst bed with continuous oxidative regeneration. The extent ofcoke loading on the catalyst can then be continuously controlled byvarying the severity and/or the frequency of regeneration. In aturbulent fluidized catalyst bed the conversion reactions are conductedin a vertical reactor column by passing hot reactant vapor upwardlythrough the reaction zone at a velocity greater than dense bedtransition velocity and less than transport velocity for the averagecatalyst particle. A continuous process is operated by withdrawing aportion of coked catalyst from the reaction zone, oxidativelyregenerating the withdrawn catalyst and returning regenerated catalystto the reaction zone at a rate to control catalyst activity and reactionseverity to effect feedstock conversion. Preferred fluid bed reactorsystems are described in Avidan et al. (U.S. Pat. No. 4,547,616);Harandi et al. (U.S. Pat. No. 4,751,338); and Tabak et al. (U.S. Pat.No. 4,579,999), each of which is incorporated herein by reference in itsentirety. In other aspects, other types of reactors can be used, such asfixed bed reactors, riser reactors, fluid bed reactors, and/or movingbed reactors.

A suitable feed can be converted to aromatics by exposing the feed to anaromatization catalyst under effective conversion conditions. Generalconversion conditions include a pressure of about 100 kPaa to about 2500kPaa, preferably about 100 kPaa to about 2000 kPaa, more preferablyabout 100 kPaa to about 1500 kPaa, and ideally about 100 kPaa to about1200 kPaa. The amount of feed (weight) relative to the amount ofcatalyst (weight) can be expressed as a weight hourly space velocity(WHSV). Suitable weight hourly space velocities include a WHSV of about0.1 hr⁻¹ to about 20 hr⁻¹, preferably about 1.0 hr⁻¹ to about 10 hr⁻¹. Awide range of temperatures can be suitable, depending on the desiredtype of aromatics-containing product. Thus, temperatures of about 300°C. to about 600° C., preferably about 300° C. to about 500° C., and morepreferably about 350° C. to about 450° C.

Aromatization Catalyst

The catalyst used herein is a composition of matter comprising amolecular sieve and a Group 8-14 element, or combination of metals fromthe same group of the Periodic Table. The composition of matter canoptionally further comprise phosphorus and/or lanthanum and/or otherelements from Group 1-2 and/or Group 13-16 of the Periodic Table thatprovide structural stabilization. In this sense, the term “comprising”can also mean that the catalyst can comprise the physical or chemicalreaction product of the molecular sieve and the Group 8-14 element orcombination of elements from the same group (and optionally phosphorusand/or lanthanum and/or other elements from groups 1-2 and/or group13-16). In this description, reference to a group number for an elementcorresponds to the current IUPAC numbering scheme for the periodictable. Optionally, the catalyst may also include a filler or binder andmay be combined with a carrier to form slurry.

In various aspects, the molecular sieve comprises ≧10.0 wt. % of thecatalyst, such about 10.0 to 100.0 wt. %, preferably about 25.0 to 95.0wt. %, and more preferably about 50.0 to 90.0 wt. %.

As used herein the term “molecular sieve” refers to crystalline ornon-crystalline materials having a porous structure. Microporousmolecular sieves typically have pores having a diameter of ≦about 2.0nm. Mesoporous molecular sieves typically have pores with diameters ofabout 2 to about 50 nm. Macroporous molecular sieves have pore diametersof >50.0 nm.

Particular molecular sieves are zeolitic materials. Zeolitic materialsare crystalline or para-crystalline materials. Some zeolites arealuminosilicates comprising [SiO4] and [AlO4] units. Other zeolites arealuminophosphates (AlPO) having structures comprising [AlO4] and [PO4]units. Still other zeolites are silicoaluminophosphates (SAPO)comprising [SiO4], [AlO4], and [PO4] units.

Non-limiting examples of SAPO and AlPO molecular sieves useful hereininclude one or a combination of SAPO-5, SAPO-8, SAPO-11, SAPO-16,SAPO-17, SAPO-18, SAPO-20, SAPO-31, SAPO-34, SAPO-35, SAPO-36, SAPO-37,SAPO-40, SAPO-41, SAPO-42, SAPO-44, SAPO-47, SAPO-56, AlPO-5, AlPO-11,AlPO-18, AlPO-31, AlPO-34, AlPO-36, AlPO-37, AlPO-46, and metalcontaining molecular sieves thereof. Of these, particularly usefulmolecular sieves are one or a combination of SAPO-18, SAPO-34, SAPO-35,SAPO-44, SAPO-56, AlPO-18, AlPO-34 and metal containing derivativesthereof, such as one or a combination of SAPO-18, SAPO-34, AlPO-34,AlPO-18, and metal containing derivatives thereof, and especially one ora combination of SAPO-34, AlPO-18, and metal containing derivativesthereof.

Additionally or alternatively, the molecular sieves useful herein may becharacterized by a ratio of Si to Al. In particular embodiments, themolecular sieves suitable herein include those having a Si/Al ratio ofabout 0.05 to 0.5.

In an embodiment, the molecular sieve is an intergrowth material havingtwo or more distinct crystalline phases within one molecular sievecomposition. In particular, intergrowth molecular sieves are describedin U.S. Patent Application Publication No. 2002-0165089 andInternational Publication No. WO 98/15496, published Apr. 16, 1998, bothof which are herein fully incorporated by reference.

Particular molecular sieves useful in this invention include ZSM-5 (U.S.Pat. No. 3,702,886 and Re. 29,948); ZSM-11 (U.S. Pat. No. 3,709,979);ZSM-12 (U.S. Pat. No. 3,832,449); ZSM-22 (U.S. Pat. No. 4,556,477);ZSM-23 (U.S. Pat. No. 4,076,842); ZSM-34 (U.S. Pat. No. 4,079,095)ZSM-35 (U.S. Pat. No. 4,016,245); ZSM-48 (U.S. Pat. No. 4,397,827);ZSM-57 (U.S. Pat. No. 4,046,685); and ZSM-58 (U.S. Pat. No. 4,417,780).The entire contents of the above references are incorporated byreference herein. Other useful molecular sieves include MCM-22, PSH-3,SSZ-25, MCM-36, MCM-49 or MCM-56, with MCM-22. Still other molecularsieves include Zeolite T, ZK5, erionite, and chabazite.

Another option for characterizing a zeolite (or other molecular sieve)is based on the nature of the ring channels in the zeolite. The ringchannels in a zeolite can be defined based on the number of atomsincluded in the ring structure that forms the channel. In some aspects,a zeolite can include at least one ring channel based on a 10-memberring. In such aspects, the zeolite preferably does not have any ringchannels based on a ring larger than a 10-member ring. Examples ofsuitable framework structures having a 10-member ring channel but nothaving a larger size ring channel include EUO, FER, IMF, LAU, MEL, MFI,MFS, MTT, MWW, NES, PON, SFG, STF, STI, TON, TUN, MRE, and PON.

In some aspects, the catalyst can also optionally include at least onemetal selected from Group 8-14 of the Periodic Table, such as at leasttwo metals (i.e., bimetallic) or at least three metals (i.e.,trimetallic). Typically, the total weight of the Group 8-14 elements isfrom about 0.1 to 10 wt. % based on the total weight of the catalyst,preferably from about 0.1 to 2.0 wt. %, and more preferably from about0.1 to 1.0 wt. %. Of course, the total weight of the Group 8-14 elementsshall not include amounts attributable to the molecular sieve itself.

Additionally or alternatively, in some aspects, the catalyst can alsoinclude at least one of phosphorous and/or lanthanum and/or otherelements from groups 1-2 and/or group 13-16, such as at least two suchelements or at least three such elements. Typically, the total weight ofthe phosphorous and/or lanthanum and/or other elements from groups 1-2and/or groups 13-16 is about 0.1 to 1.0 wt. % based on the total weightof the catalyst. Of course, the total weight of the phosphorous and/orlanthanum and/or other elements from groups 1-2 and/or groups 13-16shall not include amounts attributable to the molecular sieve itself.

For the purposes of this description and claims, the numbering schemefor the Periodic Table Groups corresponds to the current IUPAC numberingscheme. Therefore, a “Group 4 metal” is an element from Group 4 of thePeriodic Table, e.g., Hf, Ti, or Zr. The more preferred molecular sievesare SAPO molecular sieves, and metal-substituted SAPO molecular sieves.In particular embodiments, one or more Group 1 elements (e.g., Li, Na,K, Rb, Cs, Fr) and/or Group 2 elements (e.g., Be, Mg, Ca, Sr, Ba, andRa) and/or phosphorous and/or Lanthanum may be used. One or more Group7-9 element (e.g., Mn, Tc, Re, Fe, Ru, Os, Co, Rh, and Ir) may also beused. Group 10 elements (Ni, Pd, and Pt) are less commonly used inapplications for forming olefins and aromatics, as the combination of aGroup 10 element in the presence of hydrogen can tend to result insaturation of aromatics and/or olefins. In some embodiments, one or moreGroup 11 and/or Group 12 elements (e.g., Cu, Ag, Au, Zn, and Cd) may beused. In still other embodiments, one or more Group 13 elements (B, Al,Ga, In, and Tl) and/or Group 14 elements (Si, Ge, Sn, Pb) may be used.In a preferred embodiment, the metal is selected from the groupconsisting of Zn, Ga, Cd, Ag, Cu, P, La, or combinations thereof. Inanother preferred embodiment, the metal is Zn, Ga, Ag, or a combinationthereof.

Particular molecular sieves and Group 2-13-containing derivativesthereof have been described in detail in numerous publications includingfor example, U.S. Pat. No. 4,567,029 (MeAPO where Me is Mg, Mn, Zn, orCo), U.S. Pat. No. 4,440,871 (SAPO), European Patent Application EP-A-0159 624 (ElAPSO where E1 is Be, B, Cr, Co, Ga, Fe, Mg, Mn, Ti, or Zn),U.S. Pat. No. 4,554,143 (FeAPO), U.S. Pat. Nos. 4,822,478, 4,683,217,4,744,885 (FeAPSO), EP-A-0 158 975 and U.S. Pat. No. 4,935,216 (ZnAPSO,EP-A-0 161 489 (CoAPSO), EP-A-0 158 976 (ELAPO, where EL is Co, Fe, Mg,Mn, Ti, or Zn), U.S. Pat. No. 4,310,440 (AlPO4), U.S. Pat. No. 5,057,295(BAPSO), U.S. Pat. No. 4,738,837 (CrAPSO), U.S. Pat. Nos. 4,759,919, and4,851,106 (CrAPO), U.S. Pat. Nos. 4,758,419, 4,882,038, 5,434,326, and5,478,787 (MgAPSO), U.S. Pat. No. 4,554,143 (FeAPO), U.S. Pat. Nos.4,686,092, 4,846,956, and 4,793,833 (MnAPSO), U.S. Pat. Nos. 5,345,011and 6,156,931 (MnAPO), U.S. Pat. No. 4,737,353 (BeAPSO), U.S. Pat. No.4,940,570 (BeAPO), U.S. Pat. Nos. 4,801,309, 4,684,617, and 4,880,520(TiAPSO), U.S. Pat. Nos. 4,500,651, 4,551,236, and 4,605,492 (TiAPO),U.S. Pat. Nos. 4,824,554, 4,744,970 (CoAPSO), U.S. Pat. No. 4,735,806(GaAPSO) EP-A-0 293 937 (QAPSO, where Q is framework oxide unit [QO2]),as well as U.S. Pat. Nos. 4,567,029, 4,686,093, 4,781,814, 4,793,984,4,801,364, 4,853,197, 4,917,876, 4,952,384, 4,956,164, 4,956,165,4,973,785, 5,241,093, 5,493,066, and 5,675,050, all of which are hereinfully incorporated by reference. Other molecular sieves include thosedescribed in R. Szostak, Handbook of Molecular Sieves, Van NostrandReinhold, New York, N.Y. (1992), which is herein fully incorporated byreference. In some aspects, the molecular sieve as modified by the Group8-14 element and/or a Group 1-2, Group 13-16, lanthanum, and/orphosphorous is a ZSM-5 based molecular sieve.

Various methods for synthesizing molecular sieves or modifying molecularsieves are described in U.S. Pat. No. 5,879,655 (controlling the ratioof the templating agent to phosphorus), U.S. Pat. No. 6,005,155 (use ofa modifier without a salt), U.S. Pat. No. 5,475,182 (acid extraction),U.S. Pat. No. 5,962,762 (treatment with transition metal), U.S. Pat.Nos. 5,925,586 and 6,153,552 (phosphorus modified), U.S. Pat. No.5,925,800 (monolith supported), U.S. Pat. No. 5,932,512 (fluorinetreated), U.S. Pat. No. 6,046,373 (electromagnetic wave treated ormodified), U.S. Pat. No. 6,051,746 (polynuclear aromatic modifier), U.S.Pat. No. 6,225,254 (heating template), International Patent ApplicationWO 01/36329 published May 25, 2001 (surfactant synthesis), InternationalPatent Application WO 01/25151 published Apr. 12, 2001 (staged acidaddition), International Patent Application WO 01/60746 published Aug.23, 2001 (silicon oil), U.S. Patent Application Publication No.2002-0055433 published May 9, 2002 (cooling molecular sieve), U.S. Pat.No. 6,448,197 (metal impregnation including copper), U.S. Pat. No.6,521,562 (conductive microfilter), and U.S. Patent ApplicationPublication No. 2002-0115897 published Aug. 22, 2002 (freeze drying themolecular sieve), which are all herein incorporated by reference intheir entirety.

Example—Improved Aromatics Yield Using Easily Convertible Oxygenates

Four different oxygenate feeds were used as feeds for an oxygenate toaromatic conversion reaction. A first feed (diamond symbols in FIG. 2)was a conventional methanol (100%) feed with an effective hydrogen indexof 2. A second feed (triangle symbols in FIG. 2) was a mixture of about70 vol % methanol and about 30 vol % acetone with an effective hydrogenindex of about 1.8. A third feed (circle symbols in FIG. 2) was amixture of about 30 vol % acetone, about 55 vol % n-butanol, about 10vol % ethanol, and about 5 vol % water, which also had an effectivehydrogen index of about 1.8. This feed is believed to be representativeof a type of acetone/n-butanol/ethanol mixture that could be generatedfrom a suitable fermentation process. The fourth feed (square symbols inFIG. 2) was a mixture of about 55 vol % acetone, about 30 vol %n-butanol, about 10 vol % ethanol, and about 5 vol % water, resulting inan effective hydrogen index of between about 1.5 and 1.6. In the feedswith effective hydrogen index of between 1.4 and 1.9, all of the feedcomponents have a hydrogen index of greater than 1.

The feeds were exposed to one of two types of aromatization catalystsunder effective conditions for conversion of oxygenates to aromatics.The conditions included a temperature of about 450° C., a weight hourlyspace velocity of about 2 hr⁻¹, and a pressure of about 15 psig (about100 kPag). At the conversion conditions, between 90 wt. % and 100 wt. %of each feed was converted. One aromatization catalyst used forperforming the conversion reaction was a phosphorous stabilized ZSM-5catalyst. The phosphorous content on the catalyst was about 1.2 wt. %relative to the total weight of the catalyst. The other aromatizationcatalyst was a ZSM-5 catalyst with 1 wt. % of Zn deposited on thecatalyst.

FIG. 2 shows aromatic selectivities for the products generated fromconverting each of the four feeds in the presence of the two types ofaromatization catalysts. In the results shown in FIG. 2, the Zn-ZSM-5catalyst had generally higher aromatics production, but the same trendof dependence of aromatic selectivity on the feed was present for bothcatalysts. As shown in FIG. 2, using a mixture of oxygenates with aneffective hydrogen index of less than 1.9 resulted in improved aromaticsselectivity (yield) relative to a conventional 100% methanol feed.Altering the mixture of oxygenates at the same feed effective hydrogenindex did not appear to alter the aromatics selectivity. Additionally,it is noted that further reducing the effective hydrogen index fromabout 1.8 to between about 1.5 and 1.6 resulted in still furtherincreases in aromatics yield. This demonstrates that improvements inaromatics yield can be obtained from oxygenate mixtures that areconventionally believed to correspond to only “easily convertible”compounds.

Example—Improved Aromatics Yield with Pyrolysis Oil Co-Feed

A feed containing methanol and a feed including about 80 vol % methanoland 20 vol % pyrolysis oil were exposed to a fixed bed of anaromatization catalyst (ZSM-5) under effective conditions for conversionof oxygenates to aromatics. The weight hourly space velocity was about 6hr⁻¹ and the pressure was about 1 atm (100 kPag). The conversion wasperformed at both 400° C. and 500° C. The conversion conditions wereeffective for substantially complete conversion of oxygenate compoundsin the feeds.

At 400° C., conversion of the methanol feed resulted in a hydrocarbonproduct where 17.2 wt. % of the products were C₆-C₉ aromatics. Using thefeed with 80 vol % methanol and 20 vol % pyrolysis oil, performing aconversion at 400° C. resulted in a hydrocarbon product where 26.4 wt. %of the products were C₆-C₉ aromatics. Similar results were observed at aconversion temperature of 500° C. Conversion of the methanol feed at500° C. resulted in a hydrocarbon product with 19.4 wt. % C₆-C₉aromatics, while conversion of the methanol/pyrolysis oil feed resultedin 26 wt. % C₆-C₉ aromatics. It is noted that attempting to process justthe pyrolysis oil feed under the conversion conditions resulting inplugging of the catalyst bed.

In addition to improving the yield of aromatics, the co-processing ofthe methanol and pyrolysis feed also resulted in conversion ofsubstantially all of the oxygenates in the pyrolysis oil intohydrocarbons. After separation of any desirable portions of theconversion effluent, such as a desired aromatics and/or naphthafraction, another valuable portion of the effluent can be an upgradedpyrolysis oil that is more suitable for further processing inconventional refinery processes.

This example demonstrates the benefits of co-processing a pyrolysis oilfeed with a high EHI oxygenate feed for aromatics production (such asgasoline production). By staging the addition of pyrolysis oil to areaction system as described herein, the benefits of co-processing ofpyrolysis oil can be achieved while reducing or minimizing the amount ofcoke production and/or fouling in the reaction system.

Although the present invention has been described in terms of specificembodiments, it is not so limited. Suitable alterations/modificationsfor operation under specific conditions should be apparent to thoseskilled in the art. It is therefore intended that the following claimsbe interpreted as covering all such alterations/modifications as fallwithin the true spirit/scope of the invention. Ranges disclosed hereininclude combinations of any of the enumerated values.

What is claimed is:
 1. A method for converting oxygenates to aromaticscomprising: exposing an oxygenate feed comprising oxygenates and havingan effective hydrogen index of about 1.5 to about 1.8 to anaromatization catalyst under effective conversion conditions to convertthe oxygenates in the feed to one or more aromatic compounds to form aconversion effluent, wherein the oxygenate feed contains 5 wt. % or lessof carbon-containing compounds different from CO and CO₂ that have ahydrogen index of 1 or less, and wherein said aromatization catalystcomprises a ZSM-5 zeolite having a ratio of silicon to aluminum of 0.05to 0.5 and at least one metal from Groups 8-14 of the Periodic Table. 2.The method of claim 1, wherein the oxygenate feed consists essentiallyof ketones, alcohols, C₃+ aldehydes, and combinations thereof.
 3. Themethod of claim 2, wherein the alcohols consist essentially of methanol,ethanol, propanol, n-butanol, and combinations thereof.
 4. The method ofclaim 1, wherein the feed contains 1 wt. % or less of carbon-containingcompounds different from CO and CO₂ that have a hydrogen index of 1 orless.
 5. The method of claim 1, wherein the feed comprises acetone,n-butanol, and ethanol.
 6. The method of claim 1, wherein the feedconsists essentially of acetone, n-butanol, and ethanol.
 7. The methodof claim 1, wherein the feed is substantially free of carboxylic acids.8. The method of claim 1, wherein the at least one element from Groups8-14 is selected from the group consisting of Zn, Ga, Ag andcombinations thereof.